U.S. patent number 10,656,582 [Application Number 16/133,725] was granted by the patent office on 2020-05-19 for image forming apparatus, non-transitory computer readable medium, and test chart.
This patent grant is currently assigned to FUJI XEROX CO., LTD.. The grantee listed for this patent is FUJI XEROX CO., LTD.. Invention is credited to Osamu Goto, Yoshiki Matsuzaki.
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United States Patent |
10,656,582 |
Goto , et al. |
May 19, 2020 |
Image forming apparatus, non-transitory computer readable medium,
and test chart
Abstract
An image forming apparatus as a first apparatus includes an
image forming unit that forms an image onto a recording medium, a
memory that stores first and second information, and a correcting
unit that corrects an image formation position by the image forming
unit in accordance with the first or second information. The first
information is for correcting misregistration between a print
position in the first apparatus and a print position in a second
image forming apparatus as a second apparatus when an image is
formed by the first apparatus and an image is subsequently formed
by the second apparatus. The second information is for correcting
misregistration between the print positions in the second and first
apparatuses when an image is formed by the first apparatus, an
image is subsequently formed by the second apparatus, and then an
image is formed by the first apparatus.
Inventors: |
Goto; Osamu (Kanagawa,
JP), Matsuzaki; Yoshiki (Kanagawa, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
FUJI XEROX CO., LTD. |
Tokyo |
N/A |
JP |
|
|
Assignee: |
FUJI XEROX CO., LTD. (Tokyo,
JP)
|
Family
ID: |
66815967 |
Appl.
No.: |
16/133,725 |
Filed: |
September 18, 2018 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20190187600 A1 |
Jun 20, 2019 |
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Foreign Application Priority Data
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Dec 15, 2017 [JP] |
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2017-240280 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G03G
15/0121 (20130101); G03G 15/5062 (20130101); G03G
15/5058 (20130101); G03G 2215/00021 (20130101); G03G
15/6561 (20130101); G03G 2215/0161 (20130101) |
Current International
Class: |
G03G
15/00 (20060101); G03G 15/01 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2008023791 |
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Feb 2008 |
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JP |
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2011069980 |
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Apr 2011 |
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JP |
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Primary Examiner: Gray; Francis C
Attorney, Agent or Firm: JCIPRNET
Claims
What is claimed is:
1. A first image forming apparatus comprising: an image forming
unit that forms an image onto a recording medium; a memory that
stores first correction information and second correction
information, the first correction information being used for
correcting misregistration between a print position in the first
image forming apparatus and a print position in a second image
forming apparatus when an image is formed by the first image
forming apparatus and an image is subsequently formed by the second
image forming apparatus, the second correction information being
used for correcting misregistration between the print position in
the second image forming apparatus and the print position in the
first image forming apparatus when an image is formed by the first
image forming apparatus, an image is subsequently formed by the
second image forming apparatus, and then an image is formed by the
first image forming apparatus; and a correcting unit that corrects
a position where the image is to be formed by the image forming
unit in accordance with either the first correction information or
the second correction information stored in the memory.
2. The first image forming apparatus according to claim 1, wherein
the first correction information is generated by using a test chart
obtained by forming a first print-position-adjustment image onto
the recording medium by using the first image forming apparatus and
subsequently forming a second print-position-adjustment image onto
the recording medium by using the second image forming apparatus,
and wherein the second correction information is generated by using
a test chart obtained by forming an image with no print data onto
the recording medium by using the first image forming apparatus,
forming the second print-position-adjustment image onto the
recording medium by using the second image forming apparatus, and
subsequently forming the first print-position-adjustment image or a
third print-position-adjustment image onto the recording medium by
using the first image forming apparatus.
3. The first image forming apparatus according to claim 2, wherein,
when the image with no print data is to be formed onto the
recording medium, a fixing process is performed without forming an
image onto the recording medium.
4. The first image forming apparatus according to claim 1, wherein
the first correction information and the second correction
information are generated by using a test chart obtained by forming
a first print-position-adjustment image onto the recording medium
by using the first image forming apparatus, forming a second
print-position-adjustment image onto the recording medium by using
the second image forming apparatus, and subsequently forming a
third print-position-adjustment image onto the recording medium by
using the first image forming apparatus.
5. The first image forming apparatus according to claim 4, further
comprising: a generating unit that generates the first correction
information from a positional relationship between the first
print-position-adjustment image and the second
print-position-adjustment image on the recording medium and that
generates the second correction information from a positional
relationship between the second print-position-adjustment image and
the third print-position-adjustment image on the recording
medium.
6. The first image forming apparatus according to claim 1, further
comprising: a receiving unit that receives selected correction
information to be used when the image forming unit forms the image
onto the recording medium, wherein the correcting unit corrects the
position where the image is to be formed by the image forming unit
in accordance with a selected one of the first correction
information and the second correction information received by the
receiving unit.
7. The first image forming apparatus according to claim 1, wherein
the image forming unit is capable of forming an image of a spot
color other than a process color onto the recording medium.
8. The first image forming apparatus according to claim 7, wherein
the image forming unit is capable of forming an image of the
process color onto the recording medium, and forms a
print-position-adjustment image of the process color in a case
where a print-position-adjustment image is to be formed on the
recording medium.
9. The first image forming apparatus according to claim 7, wherein
the process color includes yellow, magenta, cyan, and black colors,
and the spot color includes a color other than the yellow, magenta,
cyan, and black colors.
10. A non-transitory computer readable medium storing a program
causing a computer to execute a process, the process comprising:
receiving selected correction information to be used when an image
is to be formed onto a recording medium; and correcting a position
where the image is to be formed onto the recording medium in
accordance with the selected correction information received in the
receiving, the selected correction information being one of first
correction information and second correction information, the first
correction information being used for correcting misregistration
between a print position in a first image forming apparatus and a
print position in a second image forming apparatus when an image is
formed by the first image forming apparatus and an image is
subsequently formed by the second image forming apparatus, the
second correction information being used for correcting
misregistration between the print position in the second image
forming apparatus and the print position in the first image forming
apparatus when an image is formed by the first image forming
apparatus, an image is subsequently formed by the second image
forming apparatus, and then an image is formed by the first image
forming apparatus.
11. A test chart obtained by forming a first
print-position-adjustment image, a second print-position-adjustment
image, and a third print-position-adjustment image onto a recording
medium, the first print-position-adjustment image being formed by a
first image forming apparatus, the second print-position-adjustment
image being formed by a second image forming apparatus after the
first print-position-adjustment image is formed, the third
print-position-adjustment image being formed by the first image
forming apparatus after the second print-position-adjustment image
is formed.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based on and claims priority under 35 USC 119
from Japanese Patent Application No. 2017-240280 filed Dec. 15,
2017.
BACKGROUND
Technical Field
The present invention relates to image forming apparatuses,
non-transitory computer readable media, and test charts.
SUMMARY
According to an aspect of the invention, there is provided an image
forming apparatus including an image forming unit, a memory, and a
correcting unit. The image forming unit forms an image onto a
recording medium. The memory stores first correction information
and second correction information. The first correction information
is used for correcting misregistration between a print position in
the image forming apparatus and a print position in a second image
forming apparatus when an image is formed by the image forming
apparatus and an image is subsequently formed by the second image
forming apparatus. The second correction information is used for
correcting misregistration between the print position in the second
image forming apparatus and the print position in the image forming
apparatus when an image is formed by the image forming apparatus,
an image is subsequently formed by the second image forming
apparatus, and then an image is formed by the image forming
apparatus. The correcting unit corrects a position where the image
is to be formed by the image forming unit in accordance with either
the first correction information or the second correction
information stored in the memory.
BRIEF DESCRIPTION OF THE DRAWINGS
Exemplary embodiments of the present invention will be described in
detail based on the following figures, wherein:
FIG. 1 illustrates a system configuration of a printing system
according to an exemplary embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating the structure of an
image forming apparatus according to an exemplary embodiment of the
present invention;
FIG. 3 illustrates a hardware configuration of a controller shown
in FIG. 2;
FIG. 4 is a block diagram illustrating a functional configuration
of the entire image forming apparatus including the controller;
FIG. 5 illustrates a specific example of correction parameters
stored in a correction-parameter storage unit;
FIG. 6 illustrates an example of a print result in a case where
additional printing is performed twice by first and second image
forming apparatuses;
FIG. 7 is a cross-sectional view of the example of the print result
shown in FIG. 6;
FIG. 8 illustrates a printing procedure in a case where a printing
process is performed three times by using the first and second
image forming apparatuses for obtaining the print result shown in
FIGS. 6 and 7;
FIG. 9A illustrates an example of a test image printed in the first
image forming apparatus, and FIG. 9B illustrates an example of a
test image printed in the second image forming apparatus;
FIG. 10 illustrates a method for generating a first correction
parameter in a case where first and second correction parameters
are to be generated from different test charts;
FIG. 11 illustrates a method for generating the second correction
parameter in a case where the first and second correction
parameters are to be generated from different test charts;
FIG. 12 illustrates a specific method for generating the first and
second correction parameters from first and second test charts;
FIG. 13 illustrates a test image printed by the first image forming
apparatus in a case where the first and second correction
parameters are to be generated from a single test chart;
FIG. 14 illustrates a method for simultaneously generating the
first and second correction parameters from the same test
chart;
FIG. 15 illustrates a specific method for generating the first and
second correction parameters from a test chart; and
FIG. 16 illustrates a specific operation method for selecting
either one of the first and second correction parameters.
DETAILED DESCRIPTION
Exemplary embodiments of the present invention will now be
described in detail with reference to the drawings.
FIG. 1 illustrates a system configuration of a printing system
according to an exemplary embodiment of the present invention.
As shown in FIG. 1, the printing system according to the exemplary
embodiment of the present invention includes two image forming
apparatuses 10A and 10B and a terminal apparatus 20 that are
connected to one another via a network.
The image forming apparatus 10B is a printer, that is, a so-called
YMCK printer, capable of forming a process-color (YMCK) image
constituted of yellow (Y), magenta (M), cyan (C), and black (K)
colors onto a recording medium, such as a printing sheet.
The image forming apparatus 10A is a printer, that is, a so-called
spot-color printer, capable of forming an image of a spot color
other than the YMCK process colors onto a recording medium. A spot
color includes various colors other than the YMCK colors, such as
metallic luster colors, including silver (Si) and gold (G) colors,
a white color (W), and a clear color. The following description
with regard to this exemplary embodiment relates to a case where
the image forming apparatus 10A is capable of forming images of
three types of spot colors, namely, silver (Si), gold (G), and
white (W) colors.
Furthermore, the image forming apparatus 10A is configured to form
a black (K) image, which is a process-color image, in addition to
the images of the three types of spot colors. The reason that the
image forming apparatus 10A is configured in this manner will be
described later.
In the printing system according to this exemplary embodiment, a
printing sheet having an image formed thereon using one of the two
image forming apparatuses 10A and 10B undergoes additional printing
by printing another image thereon using the other image forming
apparatus.
In particular, in this exemplary embodiment, when an image forming
process is to be sequentially performed three times on the same
printing sheet by alternately using the two image forming
apparatuses 10A and 10B, a positional adjustment is performed for
reducing misregistration between the print positions of the two
image forming apparatuses 10A and 10B.
Next, the structure of the image forming apparatus 10A shown in
FIG. 1 will be described with reference to FIG. 2. FIG. 2 is a
cross-sectional view illustrating the structure of the image
forming apparatus 10A according to this exemplary embodiment. The
structure of the image forming apparatus 10B only differs from that
of the image forming apparatus 10A in that the toners set therein
are process-color toners, that is, YMCK toners, instead of
spot-color toners. Therefore, a description regarding the structure
of the image forming apparatus 10B will be omitted.
The image forming apparatus 10A has a printing device 21 and an
image reading device 34. The printing device 21 has, for example,
three recording-medium feed cassettes 22, and these
recording-medium feed cassettes 22 are respectively provided with
feed heads 23.
When one of the recording-medium feed cassettes 22 is selected, the
feed head 23 is actuated so that a recording medium is fed from the
selected recording-medium feed cassette 22 to an image forming
section 25 via a recording-medium feed path 24.
The image forming section 25 is provided with white (W), silver
(Si), gold (G), and black (K) photoconductors 26 arranged
side-by-side, and is also provided with an intermediate transfer
belt 27.
Each photoconductor 26 is surrounded by, for example, a charging
device, an exposure device, a developing device, a first-transfer
device, and a cleaning device (not shown), thereby constituting an
image forming unit that forms an image for each color onto a
recording medium. A toner image formed on each photoconductor 26 is
transferred onto the intermediate transfer belt 27.
The toner images on the intermediate transfer belt 27 are
transferred onto a transported recording medium by a
second-transfer roller 28 and are fixed to the recording medium by
a fixing device 29. The recording medium having the toner images
fixed thereto is output to an output tray 31 via a recording-medium
output path 30.
If duplex printing is set, the recording medium having the images
fixed to the front face thereof by the fixing device 29 is
transported from the recording-medium output path 30 to an
inverting device 32. The recording medium is inverted by this
inverting device 32, is transported to a recording-medium inverting
path 33, is returned to the recording-medium feed path 24 again,
and is transported to the image forming section 25 where printing
is performed on the back face of the recording medium.
The image reading device 34 has an automatic document feeder 35
capable of reading both faces of a document. The document is
transported to a platen 36 by the automatic document feeder 35, and
an image of the document on the platen 36 is read by a reader
constituted of, for example, a charge coupled device (CCD). The
automatic document feeder 35 also serves as a platen cover. A
document may be placed on the platen 36 by opening this platen
cover. The opening and closing of the platen cover are detectable
by a platen-cover open-close detector.
The image forming apparatus 10A is provided with a facsimile modem
connected to a public line and a network communication device
connected to a network, such as a local area network (LAN). By
using the network communication device provided in the image
forming apparatus 10A, an image read by the image reading device 34
is transmittable to a terminal connected to the network. By
executing such a process, the image forming apparatus 10A also
functions as a facsimile transmitter.
The image forming apparatus 10A is also provided with a controller
37 for controlling various components, such as the image forming
section 25. The printing device 21 and the image reading device 34
perform, for example, a printing process and an image reading
process based on control by the controller 37.
FIG. 3 illustrates a hardware configuration of the controller
37.
As shown in FIG. 3, the controller 37 includes a central processing
unit (CPU) 11, a memory 12, a storage device 13, such as a hard
disk drive, and a communication interface (IF) 14 that transmits
and receives data to and from an external apparatus via a network.
These components are connected to one another via a control bus
15.
The CPU 11 executes a predetermined process based on a control
program stored in the memory 12 or the storage device 13 so as to
control the operation of the controller 37. Although the CPU 11 in
this exemplary embodiment is configured to read and execute the
control program stored in the memory 12 or the storage device 13,
the program may be provided to the CPU 11 by being stored in a
storage medium, such as a compact disc read-only memory
(CD-ROM).
FIG. 4 is a block diagram illustrating a functional configuration
of the entire image forming apparatus 10A including the controller
37 realized by executing the aforementioned control program.
As shown in FIG. 4, the image forming apparatus 10A according to
this exemplary embodiment includes the controller 37, a display
unit 43, an operation input unit 44, a print-job receiving unit 45,
an image reading unit 46, and an image output unit 47. The
controller 37 includes a print controller 41 and a
correction-parameter storage unit 42.
The print-job receiving unit 45 receives a print job (i.e., a print
command) transmitted from the terminal apparatus 20.
The print controller 41 performs control for generating print data
based on the print job received by the print-job receiving unit 45
and for outputting the generated print data from the image output
unit 47.
The display unit 43 is controlled by the controller 37 and displays
various types of information to a user. The operation input unit 44
receives various types of operation information input by the user.
The display unit 43 and the operation input unit 44 constitute a
so-called operation panel.
Based on control by the print controller 41, the image output unit
47 outputs an image onto a recording medium, such as a printing
sheet, having undergone various processes, such as charging,
exposure, developing, transfer, and fixing processes.
When the image is to be formed on the recording medium at the image
output unit 47, the correction-parameter storage unit 42 stores a
correction parameter (correction information) used for correcting
the image formation position, that is, the print position.
FIG. 5 illustrates a specific example of correction parameters
stored in the correction-parameter storage unit 42. In the image
forming apparatus 10A according to this exemplary embodiment, the
correction-parameter storage unit 42 stores two pieces of
correction information, namely, first and second correction
parameters.
In order to simplify the description in this exemplary embodiment,
each correction parameter includes two types of correction amounts,
namely, a "vertical displacement amount" and a "horizontal
displacement amount", as shown in FIG. 5. However, since actual
print-position misregistration includes multiple misregistration
components caused by various displacement amounts, the correction
parameters may also include various correction amounts, such as a
trapezoidal distortion amount, a vertical-parallelogram distortion
amount, a horizontal-parallelogram distortion amount, vertical
magnification, and horizontal magnification, in addition to the
above correction amounts.
The first correction parameter is correction information used for
correcting misregistration between the print position in the image
forming apparatus 10A and the print position in the other image
forming apparatus 10B when an image is formed by the image forming
apparatus 10A and another image is subsequently formed by the other
image forming apparatus 10B.
The second correction parameter is correction information used for
correcting misregistration between the print position in the other
image forming apparatus 10B and the print position in the image
forming apparatus 10A when an image is formed by the image forming
apparatus 10A, another image is subsequently formed by the other
image forming apparatus 10B, and then another image is formed by
the image forming apparatus 10A.
The print controller 41 corrects the image formation position of
the image to be formed by the image forming units in the image
output unit 47 in accordance with either the first correction
parameter or the second correction parameter stored in the
correction-parameter storage unit 42.
The reasons for correcting the print position by using the first
and second correction parameters in this manner will be described
below. The first and second correction parameters are used when
additional printing is to be performed twice by performing a first
step of using the image forming apparatus 10A to form an image
including a spot color onto a printing sheet, a second step of
using the image forming apparatus 10B to form an image of YMCK
colors, which are process colors, and a third step of using the
image forming apparatus 10A to form another image including a spot
color.
A specific example where such additional printing is performed
twice by using the image forming apparatuses 10A and 10B will be
described below with reference to FIGS. 6 to 8.
The following description relates to a case where a printing
process for obtaining a print result shown in FIG. 6 is
executed.
In the example of the print result shown in FIG. 6, a silver (Si)
image 51 is formed on a white printing sheet 50, a YMCK image 52 is
formed on the silver image 51, and a white (W) text image 53W and a
gold (G) text image 53G are finally formed on the YMCK image
52.
FIG. 7 is a cross-sectional view of the example of the print result
shown in FIG. 6. In the cross-sectional view shown in FIG. 7, the
silver (Si) image 51, the YMCK image 52, and the white (W) or gold
(G) text image 53W or 53G are sequentially formed on the printing
sheet 50.
In order to obtain the print result shown in FIGS. 6 and 7, it is
necessary to perform the printing process three times by using the
image forming apparatuses 10A and 10B. The printing sequence of
this three-step printing process will be described below with
reference to FIG. 8.
The first step involves forming the silver image 51 onto the
printing sheet 50 by using the image forming apparatus 10A as a
spot-color printer (first printing).
The second step involves forming the YMCK image 52 onto the
printing sheet 50 having the silver image 51 formed thereon by
using the image forming apparatus 10B as a YMCK printer.
The third step involves forming the white (W) and gold (G) text
images 53W and 53G onto the printing sheet 50 having the YMCK image
52 formed thereon by using the image forming apparatus 10A as a
spot-color printer (second printing).
Because a printing sheet contains moisture, the printing sheet
passing through the fixing device undergoes a slight change in
sheet size due to the moisture partially evaporating in accordance
with heat. Thus, when an image is formed on the printing sheet in a
certain image forming apparatus and another image is to be formed
again on the printing sheet in another image forming apparatus, the
print positions may sometimes deviate from each other. Therefore,
in a case where images are to be formed on the same printing sheet
50 by using the two above-described image forming apparatuses 10A
and 10B, the image formation positions have to be adjusted.
In particular, when performing the three-step printing process on
the same printing sheet, which involves the first printing step of
using the image forming apparatus 10A, the printing step of using
the image forming apparatus 10B, and the second printing step of
using the image forming apparatus 10A, as described above, a
two-step positional adjustment process that involves a positional
adjustment between the image forming apparatus 10A (first printing)
and the image forming apparatus 10B and a positional adjustment
between the image forming apparatus 10B and the image forming
apparatus 10A (second printing) is necessary.
The reason for this is that, because moisture in a printing sheet
evaporates every time the printing sheet undergoes a fixing
process, the sheet size of the printing sheet slightly changes
every time the printing sheet undergoes a fixing process, meaning
that a positional adjustment is necessary for the number of times
the printing sheet undergoes a fixing process.
Specifically, in the sequence of the printing process shown in FIG.
8, the image forming apparatus 10A (first printing) forms an image
onto the printing sheet 50 that has not undergone a fixing process,
and the image forming apparatus 10B forms an image onto the
printing sheet 50 that has undergone a single fixing process. Then,
the image forming apparatus 10A (second printing) forms an image
onto the printing sheet 50 that has undergone two fixing
processes.
Therefore, the first correction parameter for correcting the print
position between the silver image 51 formed by the image forming
apparatus 10A (first printing) and the YMCK image 52 formed by the
image forming apparatus 10B is generated and is stored in the
correction-parameter storage unit 42.
Moreover, the second correction parameter for correcting the print
position between the YMCK image 52 formed by the image forming
apparatus 10B and the white and gold text images 53W and 53G formed
by the image forming apparatus 10A (second printing) is generated
and is stored in the correction-parameter storage unit 42.
Next, a method for generating these first and second correction
parameters will be described.
The first correction parameter is generated by using a test chart
obtained by forming a first test image (print-position-adjustment
image) onto a printing sheet by using the image forming apparatus
10A and then forming a second test image onto the same printing
sheet by using the image forming apparatus 10B.
The second correction parameter is generated by using a test chart
obtained by forming an image with no print data onto a printing
sheet by using the image forming apparatus 10A, forming a second
test image onto the same printing sheet by using the image forming
apparatus 10B, and then forming the first test image or a third
test image different from the first test image onto the same
printing sheet by using the image forming apparatus 10A.
When the image forming apparatus 10A is to form the image with no
print data onto the printing sheet in the case where the second
correction parameter is to be generated, the image forming
apparatus 10A does not perform an image forming process on the
printing sheet but executes a process involving a fixing
process.
If the first and second correction parameters are to be generated
simultaneously, the first and second correction parameters are
generated by using a test chart obtained by forming a first test
image onto a printing sheet by using the image forming apparatus
10A, forming a second test image onto the same printing sheet by
using the image forming apparatus 10B, and then forming a third
test image onto the same printing sheet by using the image forming
apparatus 10A.
Specifically, this test chart is obtained by forming, on the
printing sheet, the first test image formed by the image forming
apparatus 10A, the second test image formed by the image forming
apparatus 10B after the first test image is formed, and the third
test image formed by the image forming apparatus 10A after the
second test image is formed.
The first and second correction parameters are generated by the
print controller 41 in the controller 37 and are stored in the
correction-parameter storage unit 42.
Specifically, if the first and second correction parameters are to
be generated simultaneously, the print controller 41 generates the
first correction parameter from the positional relationship between
the first test image and the second test image on the test chart,
and generates the second correction parameter from the positional
relationship between the second test image and the third test image
on the test chart.
When the image forming apparatus 10A is to perform a printing
process, the user designates which one of the two correction
parameters is to be used for adjusting the print position.
Specifically, the operation input unit 44 receives the selected
correction parameter to be used when the image forming units in the
image output unit 47 are to form an image onto a printing
sheet.
Then, the print controller 41 corrects the image formation position
of the image to be formed by the image forming units in the image
output unit 47 in accordance with the correction parameter selected
from the first and second correction parameters and received by the
operation input unit 44.
In the image forming apparatus 10A according to this exemplary
embodiment, one of the four image forming units is capable of
forming a K image, which is a process color image, onto a printing
sheet. In a case where a test image is to be formed on a printing
sheet, the test image is formed by using the K color that is
readily detectable when the test image is printed on a white
printing sheet.
Next, a specific method for generating the first and second
correction parameters described above will be described in detail
with reference to the drawings.
First, the following description with reference to FIGS. 9A to 12
relates to a case where the first and second correction parameters
are generated from different test charts.
FIG. 9A illustrates an example of a test image printed in the image
forming apparatus 10A, and FIG. 9B illustrates an example of a test
image printed in the image forming apparatus 10B. These test images
may be stored and be printed in the image forming apparatuses 10A
and 10B, or the terminal apparatus 20 may command the image forming
apparatuses 10A and 10B to print such test images.
First, a method for generating the first correction parameter will
be described with reference to FIG. 10.
First, the image forming apparatus 10A prints the test image (first
test image) shown in FIG. 9A onto a printing sheet 60 not having
any images printed thereon.
Subsequently, the image forming apparatus 10B prints the test image
(second test image) shown in FIG. 9B onto a printing sheet 61
having the first test image printed thereon.
A test chart 62 having these two test images printed thereon is
read (scanned) by the image reading unit 46 of the image forming
apparatus 10A, whereby the first correction parameter is
generated.
Next, a method for generating the second correction parameter will
be described with reference to FIG. 11.
First, the image forming apparatus 10A prints an image not having
print data onto a printing sheet 70 not having any images printed
thereon. Specifically, although an image is not formed on the
printing sheet 70, the printing sheet 70 is actually output after
undergoing various types of processes, such as a charging process,
an exposure process, a developing process, a transfer process, and
a fixing process. In other words, although there is no change in
appearance between a printing sheet 71 output after undergoing
these various types of processes and the printing sheet 70 before
the printing process, the sheets 71 and 70 have different sizes
since the sheet 71 has moisture evaporated therefrom as a result of
undergoing the fixing process.
Subsequently, the image forming apparatus 10B prints the test image
(second test image) shown in FIG. 9B onto the printing sheet 71
that has undergone the first fixing process.
Then, the image forming apparatus 10A prints the test image (first
test image) shown in FIG. 9A onto a printing sheet 72 having the
second test image printed thereon.
Subsequently, a test chart 73 having the two test images printed
thereon is read (scanned) by the image reading unit 46 of the image
forming apparatus 10A, whereby the second correction parameter is
generated.
A specific method for generating the first and second correction
parameters from the test charts 62 and 73 will now be described
with reference to FIG. 12.
The print controller 41 of the image forming apparatus 10A extracts
the positional relationship between the two test images shown in
FIG. 12 from the images of the test charts read by the image
reading unit 46 and generates the first and second correction
parameters based on the extracted positional relationship.
Specifically, if the position of a test image generated by the
image forming apparatus 10A and the position of a test image
generated by the image forming apparatus 10B is known in advance,
correction parameters to be used for correcting the positional
relationship between two images to be actually printed are
generable by detecting a deviation in the positional relationship
between actually-read test images. Although FIG. 12 corresponds to
a case where a position in one test image is compared with a
position in another test image, the correction parameters are
actually generated by comparing multiple positions in test
charts.
Then, the print controller 41 generates the first correction
parameter from the test chart 62, generates the second correction
parameter from the test chart 73, and causes the
correction-parameter storage unit 42 to store the first and second
correction parameters.
The following description with reference to FIGS. 13 to 15 relates
to a case where the first and second correction parameters are
generated from a single test chart.
In this case, the image forming apparatus 10A is capable of
printing a test image shown in FIG. 13 in addition to the test
image shown in FIG. 9A.
A method for simultaneously generating the first and second
correction parameters from the same test chart will be described
below with reference to FIG. 14.
First, the image forming apparatus 10A prints the test image (first
test image) shown in FIG. 9A onto a printing sheet 80 not having
any images printed thereon.
Subsequently, the image forming apparatus 10B prints the test image
(second test image) shown in FIG. 9B onto a printing sheet 81
having the first test image printed thereon.
Then, the image forming apparatus 10A prints the test image (third
test image) shown in FIG. 13 onto a printing sheet 82 having the
aforementioned test images printed thereon.
Subsequently, a test chart 83 having the three test images printed
thereon is read (scanned) by the image reading unit 46 of the image
forming apparatus 10A, whereby the first and second correction
parameters are generated.
A specific method for generating the first and second correction
parameters from the test chart 83 will now be described with
reference to FIG. 15.
With reference to the test image (second test image) printed by the
image forming apparatus 10B in the image of the test chart 83 read
by the image reading unit 46, the print controller 41 of the image
forming apparatus 10A generates the first correction parameter
based on the positional relationship with the test image (first
test image) printed by the image forming apparatus 10A in the first
printing step, and generates the second correction parameter based
on the positional relationship with the test image (third test
image) printed by the image forming apparatus 10A in the second
printing step.
Finally, a specific operation method for selecting either one of
the first and second correction parameters generated in accordance
with the above-described method will be described with reference to
FIG. 16.
For example, as shown in FIG. 16, the image forming apparatus 10A
allows either one of the first and second correction parameters to
be selectable on an operation panel 90.
Then, in a case where the printing process is to be performed three
times by using the image forming apparatuses 10A and 10B in
accordance with the printing method shown in FIG. 8, the first
correction parameter is selected when the silver image 51 is to be
formed onto the printing sheet 50 by the image forming apparatus
10A as a spot-color printer (first printing).
Subsequently, the second correction parameter is selected when the
white (W) and gold (G) text images 53W and 53G are to be formed
onto the printing sheet 50 having the YMCK image 52 formed thereon
by using the image forming apparatus 10A as a spot-color printer
(second printing).
Modifications
In the above exemplary embodiment, the three printing steps are
sequentially performed on the same printing sheet by using the
image forming apparatus 10A as a spot-color printer (first
printing), the image forming apparatus 10B as a YMCK printer, and
the image forming apparatus 10A as a spot-color printer (second
printing) in that order. Alternatively, the exemplary embodiment of
the present invention is similarly applicable to a case where the
three printing steps are sequentially performed on the same
printing sheet by using the image forming apparatus 10B as a YMCK
printer (first printing), the image forming apparatus 10A as a
spot-color printer, and the image forming apparatus 10B as a YMCK
printer (second printing) in that order.
In this case, the first and second correction parameters may be
stored in the image forming apparatus 10B so that a positional
adjustment for reducing misregistration between the print positions
of the two image forming apparatuses 10A and 10B may be performed
in accordance with a procedure similar to that described above.
The foregoing description of the exemplary embodiments of the
present invention has been provided for the purposes of
illustration and description. It is not intended to be exhaustive
or to limit the invention to the precise forms disclosed.
Obviously, many modifications and variations will be apparent to
practitioners skilled in the art. The embodiments were chosen and
described in order to best explain the principles of the invention
and its practical applications, thereby enabling others skilled in
the art to understand the invention for various embodiments and
with the various modifications as are suited to the particular use
contemplated. It is intended that the scope of the invention be
defined by the following claims and their equivalents.
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